"El Polaquito" is a street kid who scrapes a living by imitating Roberto Goyeneche, "Polaco", one of the most famous Argentine tango performers, in train carriages at the Estación Constitución in Buenos Aires. There he meets and falls in love with "La Pelu", a prostitute at the same station. Both are under the strict daily control of "Rengo" Carbajal, a false bootblack who exploits the kids and, in collusion with the police, runs all of the underhand dealings at the station.